The Pharmacokinetics (PK) Shared Resource is a shared resource that functions as a specialized service laboratory providing technical support to investigators who wish to quantify small molecule concentrations in clinical or preclinical material. The PSR provides consultation on design of pharmacokinetic studies and assistance with the analysis of PK data. The Specific Aims of the facility are: 1) to provide Cancer Institute members access to state of the art LC and GC mass spectrometry and HPLC equipment; 2) to provide Institute members with a full service laboratory that can develop analytical methods, prepare samples and provide data analysis for both clinical and basic science investigations, and 3) to provide Institute members with assistance in the design and interpretation of pharmacokinetic and pharmacodynamic studies for both animal models and Phase I investigations.